The present invention relates to a control system for a copier and, more particularly, to a control system for an electronic copier of the type having a monocolor or multicolor printing function, a combining function, a shifting function, a trimming function, a continuous printing function, a magnification changing function, and others.
A modern high-performance copier has various functions such as a monocolor or multicolor printing function, a combining function for printing images a plurality of times on a single paper, a shifting function for printing an image by shifting the display position of a document, a trimming function for printing only a part of a document, a continuous printing function for printing images of a plurality of objects carried on, for example, an A3 document on papers of smaller than the document format by dividing the objects, and a magnification changing function for printing an image of a document by enlarging or reducing the image.
In a prior art copier of the type described, each of the functions is accomplished by setting data only once when it is not accompanied by another. To execute two different functions together, after an image has been printed out with data on the first function set, data on the other function is set to print out an image on the same paper. For example, in a combining mode which includes a trim mode and a shift mode, data for trimming or shifting is set, an image is printed out, then another document data to be combined is set, then the data is printed out combined with the previous one. In this manner, data has to be registered by two consecutive times of manipulation on a function-by-function basis. Such not only forces troublesome manipulations upon the operator but also frequency invites erroneous manipulation, faulty printing, and other undesirable occurrences.
Although a special mode capable of executing such settings at the same time may be proposed, it will never occur that after the first copying operation the same mode is needed, e.g., that after the trim mode has been set and executed, the same trimming data is set for the next mode. Hence, repeating the same mode would limit the user's editing ability and data correcting ability.
Further, such a high performance copier is operated to reproduce a document image by changing the magnification to 110%, 100%, 94%, 78%, 64% or the like, the center of an image is unavoidably shifted based on the magnification selected. Also, the amount of shift is changed according to the magnification. This makes it difficult for the user to edit an image because the position of an image to be reproduced on a paper differs from that of an image printed out on a document. For example, when the trim mode or the image shift mode is combined with the magnification change mode or when combine is combined with the magnification change mode, even if a shift area is specified, the image is shifted by an amount which is produced by multiplying it by the magnification selected; converting the amount of shift to a specified one would make the editing work more difficult.
When it is desired to provide a margin on a paper for a binding purpose, a particular amount of shift is specified to shift an image to the right or to the left relative to a paper (shift mode). Specifically, since a paper is discharged upside down, right shift has to be executed by delaying the timing for causing register rollers to drive a paper while left shift has to be executed by delaying the timing for turning on a lamp. To shift an image in such a direction that a paper precedes the image, it has been customary to start the register rollers (paper) by a signal from a scanner. However, an image cannot be shifted beyond a certain limit.
As regards the continuous copy mode, it is a common practice to reproduce two discrete images carried on a single document independently of each other on two papers each being of a format double the format of the document. Although such a mode is desirably applicable to a case wherein a plurality of documents are to be divided, it is incapable of reproducing a plurality of images on papers of large format or reproducing a plurality of documents on a single paper of large format with images positioned side by side. A difficulty is also experienced in bookbinding.